Miniproposals

Miniproposal: 148 Date Filed: 7/16/1996 Title: RF Conditioning and Testing First Author: Yuichi Takase Session Leader: Steve Wukitch (shots 1-29)

Engineering Operator Run Comment

mp148 HUTCHINSON,WUKITCH,SILVA,COCHRAN,BERTOLINO

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:17:430PM

Author: To Be Determined

The RF portion of this run is to condition and test the antenna (MP148 80 MHz RF conditioning and testing). The conditioning goal is 2.5 MW (total) reliably from both transmitters. When reached, the RF will be characterized as conditioned. To accomplish this, several items need to be accomplished: 1.) FMIT#2 needs to run more consistently 2.) check position feedback 3.) condition up to maximum power Plasmas will be typical 5.4 T, 0.8-1.0 MA, D(H) heated discharges. Upon reaching the 2.5 MW reliably criterion, the RF conditioning and testing will be complete. The plan is to get E-port to work reliably (because the position feedback uses the ratio Prefl/Pforw from E-port). Using E-port as a window, D-port will be injected within the E-port time window. ST1 PS1 ST2 PS2 001 PRF(D/E)=0.75 MW with a brief ramp 0.6 < E-port < 1.2 0.8 < D-port < 1.18 plasma 581 427 2362 1105 good step to 0.5 MW on both transmitters E-port has a couple trips type I elms were present 002 fizzle 596 422 2431 1063 003 plasma D-port is running fairly reliable at 1 MW, but E has a few trips 004 plasma 2455 1065 005 plasma 006 plasma 007 plasma raised the density which caused the loading to increase from about 5 ohms to over 15 ohms 008 dud 550 477 2255 1150 009 OH2 breaker pull 010 plasma RF trips are synchronous the feedback is only giving signal when the xmtrs have tripped 011 fizzle 012 plasma changed feedback threshold to 2.8 V feedback seemed to work better 013 plasma changed feedback threshold to 2.7 V and the hybrid gain is -1800 014 plasma changed feedback threshold to 2.6 V the hybrid gain is -2000 587 432 2392 1100 whahoo only one trip *** 2.6 V Bira voltage is about 11 ohms *** 015 plasma changed feedback hybrid gain to -2200 plasma loading is much more consistent -- 2.6 V threshold corresponds to about 7 ohms of loading 016 plasma raised the RF power -- 4 trips on E and 2 on D PRF = 2.5 MW 017 plasma changed threshold voltage to 2.7 V 579 432 2368 1134 018 plasma still having faults 019 plasma changed feedback hybrid gain to -2000 still faulting 020 plasma moved the plasma away from antenna by about 4 mm 021 TF breaker pulled 022 moving the plasma further away still -- outer gap is about at 0.8 cm E-port is faulting 023 change the timing -> D-port is on first now disrupted 0.77 sec 024 changed feedback hybrid gain -1500 feedback threshold is 3 V 587 426 2482 1036 fizzle 025 plasma but the threshold is too high in voltage (too low of a loading) 027 fizzle 028 plasma feedback threshold = 2.9 V 604 409 2576 948 029 fizzle Bira [V] E-port RL D-port RL outer gap sig (E-port RL) 2.6 11.0 ohms 7 ohms .1 V @8 ohms 2.7 9 ohms 6.5 ohms .1 V @6.5 ohms 2.8 8 ohms 6.5 ohms 2.9 7.0 ohms 5 omhs .1 V @4+ ohms 3.0 5.0 ohms 4 ohms .1 V @3.5 ohms The run was largely an excersize in learning the plasma position feedback characteristics. Although the circuit was tested on the bench top, determining its characteristics required plasma discharges. After convincing ourselves that E-port was performing properly, the charge was to get the transmitters to run together which means dealing with the loading change associated with an L-H transition. We iterated towards one solution which had a loading of about 10 ohms, but this required and outer gap which was less than 4 mm. This was deemed unacceptable because of associated impurity production and the small margin of error before the plasma crashed into the antenna. We began interating towards a solution with an outer gap between 5-8 mm, but did not arrive at a conclusion before the last discharge. The erratic behavior of the plasma loading contributed to the difficulty in finding an optimum position feedback BiRa voltage and hybrid gain. Shown above is a table which gives a rough estimate of the loading which the feedback signal starts trying to pull the plasma towards the antenna (increase the loading). Higher loading has a broader region which requires little feedback. This can also be stated as higher loading cases have lower circuit Q. The balance that must be struck is one where the outer gap is acceptable (lowers the loading but not dramatically) and a load with a low enough Q to handle the L-H transition induced loading change. There are also several other options to pursue. First, use tuned demodulators to monitor the forward and reflected power at DC2 (the ratio is used as signal which the position feedback is monitoring). Such a detector was installed after the run. Second we need to evaluate the threshold level of the arc detectors. Presently, the arc detectors indicate a fault when the reflected power is 25% of the forward. Raising this to 40-50% should decrease the number of faults without jepordizing the transmitters because an arc is a fast, nonlinear event.

Physics Operator Summaries

Entered: Jul 7 2004 04:36:58:100PM

Author: To Be Determined

Physop 971209. RF conditioning. MP 148. [Re]Discovered today. _____________________ RF feedback control gain in the RCUR predictor should not be raised above a magnitude of (-)1500 no matter how persistently the RF folks plead. If you do raise it (we went as high as -2200) then eventually, the RF will succeed in blowing away the plasma by putting too high a voltage demand during RCUR excursions, saturating the chopper, and losing vertical control. The effects appear to be rather nonlinear above the 1500 level. We started with the plasma very close to the outboard limiter, the RF feedback seemed to be pulling it out till it touched. Mo levels (or at least radiated power levels) are high and there is some suggestion that the level was reduced by moving the plasma in (away from the limiter). This movement, later in the run, did not much affect the RF resistance, but the RF did not find it as easy to restart the transmitters with the bigger gap. Strike-points started low and were moved up through the run. The plasma was also moved up somewhat without any problems. After the disruption that the RF-feedback caused, we got a fizzle and never got back to reliable plasmas, although it is not clear why. Overall, behaves like a poorly boronized machine, with rapid impurity accumulation during H-modes. Scorecard _________ Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 1.575 1.014 2 0.000 0.027 3 1.580 1.014 4 1.550 1.014 5 1.525 1.009 6 1.523 1.011 7 1.375 1.009 8 0.000 0.027 9 0.000 0.009 10 1.436 1.006 11 0.000 0.037 12 1.485 1.009 13 1.480 1.006 14 1.452 1.011 15 1.436 1.011 16 1.436 1.014 17 1.456 1.014 18 1.575 1.014 19 1.595 1.014 20 1.466 1.014 21 0.000 0.025 22 1.472 1.014 23 0.773 1.019 24 0.000 0.032 25 1.534 1.014 26 0.000 0.027 27 0.000 0.037 28 1.482 1.019 29 0.000 0.027 Finished summary for 971209 Total of 29 shots. 29 shots. 20 plasmas. 8 fizzles. 1 duds. Fizzle = gt 20 lt 50kA. Logbook Entries _______________ Entry display output on Tue Dec 9 17:19:31 1997 -------------------------------------------------------------------------------- 971209xxx HUTCH PHYSICS_OPERATOR 9-DEC-1997 08:53:23.44 . . . . . . . . . . . . . . . . . . . . RF Conditioning. Minproposal 148. Ran cold start. No errors. Settings as yesterday. Plena etc: B_top 6.35 psi D2; K-side 20.33 D2; Bsidelower 2.75 Ar. Fill puff is 19ms. Load PCS. -------------------------------------------------------------------------------- 971209001 HUTCH PHYSICS_OPERATOR 9-DEC-1997 09:08:16.62 . . . . . . . . . . . . . . . . . . . . Plasma till 1.57s. 1.6 MW RF. Giant elms at .85, .92s, 1.09s. A big vertical instability oscillation at 0.25-0.35s. Freq: 100 Hz. -------------------------------------------------------------------------------- 971209002 HUTCH PHYSICS_OPERATOR 9-DEC-1997 09:21:45.93 . . . . . . . . . . . . . . . . . . . . No changes to PCS. Fizzle. Last shot had a serious hesitation. EF3 Voltage trace shows lots of hash. Lower OH1 voltage at 5ms to +100V from about +180V. To make vertical field rise quicker. -------------------------------------------------------------------------------- 971209003 HUTCH PHYSICS_OPERATOR 9-DEC-1997 09:38:25.79 . . . . . . . . . . . . . . . . . . . . Plasma to 1.56s. Still have the oscillation. EF3 noise goes away. Current hesitation is gone. 2MW RF. Move RCUR to .666m at .3s. -------------------------------------------------------------------------------- 971209004 HUTCH PHYSICS_OPERATOR 9-DEC-1997 10:01:45.21 . . . . . . . . . . . . . . . . . . . . Plasma till 1.56s. No improvemnet to oscillations. 2.2MW RF. RF loading feedback to -2000 from -1500 in segment 2. -------------------------------------------------------------------------------- 971209005 HUTCH PHYSICS_OPERATOR 9-DEC-1997 10:17:45.16 . . . . . . . . . . . . . . . . . . . . Plasma to 1.5s. Lower proportional gain from 8 to 6 one zcur 3 at .24s. -------------------------------------------------------------------------------- 971209006 HUTCH PHYSICS_OPERATOR 9-DEC-1997 10:38:52.49 . . . . . . . . . . . . . . . . . . . . Plasma to 1.5s. Major improvement in early oscillation. Go further on the zcur. Add gain to4 at 0.26s in addition to the gain 6 point at .24s. Raise nl04 demand to 1.5 at .5s. Raise kside main puff pressure to 29 psi. -------------------------------------------------------------------------------- 971209007 HUTCH PHYSICS_OPERATOR 9-DEC-1997 10:49:43.83 . . . . . . . . . . . . . . . . . . . . Plasma till 1.3s No RF. Gas stays on quite late. Eas off on the nl04 demand at about .3s. Raise zxl to -.015m to put strike points on the plate. -------------------------------------------------------------------------------- 971209008 HUTCH PHYSICS_OPERATOR 9-DEC-1997 11:04:52.84 . . . . . . . . . . . . . . . . . . . . fizzle - fields look normal - gas o.k. no sparker no changes for 009 -------------------------------------------------------------------------------- 971209009 HUTCH PHYSICS_OPERATOR 9-DEC-1997 11:24:08.53 . . . . . . . . . . . . . . . . . . . . Dud OH2L pulls out @ -0.7sec all power supplies check out o.k. -------------------------------------------------------------------------------- 971209010 HUTCH PHYSICS_OPERATOR 9-DEC-1997 11:42:59.07 . . . . . . . . . . . . . . . . . . . . plasma - disrupts @ 1.43sec - breakdown @ 5msec - sparker worked - still a density burst @ 0.43sec for 011: slow down NL04 ramp (reaches maximum @ 0.65sec) draw PG3 voltage to 50V after 0.25sec -------------------------------------------------------------------------------- 971209011 HUTCH PHYSICS_OPERATOR 9-DEC-1997 12:03:05.50 . . . . . . . . . . . . . . . . . . . . Fizzle breakdown at 6msec no sparker on this one Br is ~ +1mTesla For 012: lower Br_0 offset to .006 -------------------------------------------------------------------------------- 971209012 HUTCH PHYSICS_OPERATOR 9-DEC-1997 12:13:50.59 . . . . . . . . . . . . . . . . . . . . plasma - breakdown @ 5msec - Br_0 oscillating around 0.mT - sparker worked - density bump @ 0.4 almost all gone for shot 013: - RF_LOAD_E to -1800 (was -2000) -------------------------------------------------------------------------------- 971209013 HUTCH PHYSICS_OPERATOR 9-DEC-1997 12:33:35.75 . . . . . . . . . . . . . . . . . . . . Plasma - breakdown at 5.5msec (sparker worked) - slight hesitation in current rise For 014: RF_LOAD_E = -2000 (was -1800) -------------------------------------------------------------------------------- 971209014 HUTCH PHYSICS_OPERATOR 9-DEC-1997 12:42:12.77 . . . . . . . . . . . . . . . . . . . . Plasma - only one RF trip - breakdown @ 5msec; no hesitation -------------------------------------------------------------------------------- 971209015 HUTCH PHYSICS_OPERATOR 9-DEC-1997 13:17:03.33 . . . . . . . . . . . . . . . . . . . . Hutch back. Increase the nl04 programming to avoid density roll over. RF feedback to -2200. Plasma till 1.44s. Vertical oscillation at .9s, about 50Hz. RF Loading seems to be better controlled. -------------------------------------------------------------------------------- 971209016 HUTCH PHYSICS_OPERATOR 9-DEC-1997 13:32:57.48 . . . . . . . . . . . . . . . . . . . . No changes. Plasma till 1.43s 2.5MW with faults. Plasma is pulled very close to the limiter by the feedback. Next shot RF threshold to 2.7 from 2.6. -------------------------------------------------------------------------------- 971209017 HUTCH PHYSICS_OPERATOR 9-DEC-1997 13:54:09.43 . . . . . . . . . . . . . . . . . . . . Plasma. Some Mo injections. Raise zcur to -.013 from -.015. Ditto zxl. Argon off. -------------------------------------------------------------------------------- 971209018 HUTCH PHYSICS_OPERATOR 9-DEC-1997 14:10:13.59 . . . . . . . . . . . . . . . . . . . . Plasma till 1.54s. RF 2.6MW a couple of trips. zcur and zxl to -.011m. RF feedback to -2000. -------------------------------------------------------------------------------- 971209019 HUTCH PHYSICS_OPERATOR 9-DEC-1997 14:24:17.42 . . . . . . . . . . . . . . . . . . . . Plasma. RF 2.6MW Still having limiter contacts. Seems to coincide with Mo influx. Move rcur to .667 from .669 to try to stop limiter bumping. ------------------------------------------------------------------------------- 971209020 HUTCH PHYSICS_OPERATOR 9-DEC-1997 14:41:34.75 . . . . . . . . . . . . . . . . . . . . Plasma. Right gap now averaging about 6mm. Mo levels somewhat reduced. rcur to .665m, more of the same. ------------------------------------------------------------------------------- 971209021 HUTCH PHYSICS_OPERATOR 9-DEC-1997 14:42:01.91 . . . . . . . . . . . . . . . . . . . . Power Supply Fault. TF breaker pulled. ------------------------------------------------------------------------------- 971209022 HUTCH PHYSICS_OPERATOR 9-DEC-1997 15:38:59.56 . . . . . . . . . . . . . . . . . . . . Plasma. 10 Hz oscillation on power supplies. Looks like an Rcur problem. RF feedback? Shows predominantly on EF4, so it might be something else. Got a right gap averaging about 1cm. Turn off nl04 feedback at .8s Maintain gas puff at 40% till 1.05s. ------------------------------------------------------------------------------- 971209022 HUTCH PHYSICS_OPERATOR 9-DEC-1997 15:57:22.59 . . . . . . . . . . . . . . . . . . . . Disrupts at .77s. Slowly growing vertical instability. Seems to have been caused by the fact the RF transmitter E, that controls feedback, was turned on later, at .7s. This makes a big R jerk and then z is lost. RF feedback to -1500. -------------------------------------------------------------------------------- 971209024 HUTCH PHYSICS_OPERATOR 9-DEC-1997 16:07:40.00 . . . . . . . . . . . . . . . . . . . . Fizzle:disruption recovery. Tweak OH1 Voltage down at 5ms. Move rxl out by about 5mm. -------------------------------------------------------------------------------- 971209025 HUTCH PHYSICS_OPERATOR 9-DEC-1997 16:29:31.89 . . . . . . . . . . . . . . . . . . . . Plasma till 1.51. Repetitive H-L cycles cuased by RF trips as the H-mode develops. Rcur pulling is drastically reduced. rxl to .003m. Bruce wants more strike-point height. -------------------------------------------------------------------------------- 971209026 HUTCH PHYSICS_OPERATOR 9-DEC-1997 16:40:05.67 . . . . . . . . . . . . . . . . . . . . Fizzle. CII is up around .003. OH1 voltage lowered some more from 3ms on. -------------------------------------------------------------------------------- 971209027 HUTCH PHYSICS_OPERATOR 9-DEC-1997 16:49:10.37 . . . . . . . . . . . . . . . . . . . . Fizzle. Obviously I am not doing the right thing, but we got 40kA before hitting something. EF4 to -1330 from -1335. -------------------------------------------------------------------------------- 971209028 HUTCH PHYSICS_OPERATOR 9-DEC-1997 17:00:53.82 . . . . . . . . . . . . . . . . . . . . Plasma till 1.45s. Signs of vertical oscillation at .55s. Barely burns out. RF coupling worse than before. Fill to 17ms from 18. -------------------------------------------------------------------------------- 971209028 HUTCH PHYSICS_OPERATOR 9-DEC-1997 17:01:07.02 . . . . . . . . . . . . . . . . . . . . Fizzle.

Session Leader Comments
Dec 9 1997 09:23:13:560AM	971209001	Steve Wukitch	ST1 PS1 ST2 PS2 001 PRF(D/E)=0.75 MW with a brief ramp 0.6 < E-port < 1.2 0.8 < D-port < 1.18 plasma 581 427 2362 1105 good step to 0.5 MW on both transmitters E-port has a couple trips type I elms were present
Dec 9 1997 09:23:50:070AM	971209002	Steve Wukitch	002 Fizzle
Dec 9 1997 09:36:32:040AM	971209003	Steve Wukitch	003 plasma D-port is running fairly reliable at 1 MW, but E has a few trips
Dec 9 1997 10:48:59:220AM	971209007	Steve Wukitch	007 plasma raised the density which caused the loading to increase from about 5 ohms to over 15 ohms
Dec 9 1997 11:26:43:900AM	971209009	Steve Wukitch	EF1 breaker pull
Dec 9 1997 11:44:18:060AM	971209010	Steve Wukitch	plasma RF trips are synchronous the feedback is only giving signal when the xmtrs have tripped
Dec 9 1997 12:54:26:170PM	971209012	Steve Wukitch	plasma changed feedback threshold to 2.8 V feedback seemed to work better
Dec 9 1997 12:54:52:530PM	971209013	Steve Wukitch	plasma changed feedback threshold to 2.7 V and the hybrid gain is -1800
Dec 9 1997 12:55:21:080PM	971209014	Steve Wukitch	plasma changed feedback threshold to 2.6 V the hybrid gain is -2000 587 432 2392 1100 whahoo only one trip
Dec 9 1997 01:09:49:010PM	971209015	Steve Wukitch	plasma changed feedback hybrid gain to -2200 plasma loading is much more consistent -- 2.6 V threshold corresponds to about 7 ohms of loading
Dec 9 1997 03:35:49:190PM	971209016	Steve Wukitch	plasma raised the RF power -- 4 trips on E and 2 on D PRF = 2.5 MW
Dec 9 1997 03:36:14:200PM	971209017	Steve Wukitch	plasma changed threshold voltage to 2.7 V 579 432 2368 1134
Dec 9 1997 03:37:08:330PM	971209018	Steve Wukitch	plasma still having faults
Dec 9 1997 04:00:08:090PM	971209019	Steve Wukitch	plasma changed feedback hybrid gain to -2000 still faulting
Dec 9 1997 04:00:36:970PM	971209020	Steve Wukitch	plasma moved the plasma away from antenna by about 4 mm
Dec 9 1997 04:00:54:390PM	971209021	Steve Wukitch	TF breaker pulled
Dec 9 1997 04:01:24:700PM	971209022	Steve Wukitch	plasma moving the plasma further away still -- outer gap is about at 0.8 cm E-port is faulting
Dec 9 1997 04:02:47:090PM	971209023	Steve Wukitch	plasma change the timing -> D-port is on first now disrupted 0.77 sec -> probably caused by the change in the RF timing (the position feedback jerked the plasma when E-port came on)
Dec 9 1997 04:03:14:330PM	971209024	Steve Wukitch	fizzle changed feedback hybrid gain -1500 feedback threshold is 3 V
Dec 9 1997 04:25:42:010PM	971209025	Steve Wukitch	plasma but the threshold is too high BiRa voltage (low loading)
Dec 9 1997 04:34:10:680PM	971209026	Steve Wukitch	fizzle
Dec 9 1997 07:09:28:950PM	971209028	Steve Wukitch	plasma feedback threshold = 2.9 V 604 409 2576 948

Physics Operator Comments
Dec 9 1997 08:53:23:440AM		Ian Hutchinson	RF Conditioning. Minproposal 148. Ran cold start. No errors. Settings as yesterday. Plena etc: B_top 6.35 psi D2; K-side 20.33 D2; Bsidelower 2.75 Ar. Fill puff is 19ms. Load PCS.
Dec 9 1997 09:08:16:620AM	971209001	Ian Hutchinson	Plasma till 1.57s. 1.6 MW RF. Giant elms at .85, .92s, 1.09s. A big vertical instability oscillation at 0.25-0.35s. Freq: 100 Hz.
Dec 9 1997 09:21:45:930AM	971209002	Ian Hutchinson	No changes to PCS. Fizzle. Last shot had a serious hesitation. EF3 Voltage trace shows lots of hash. Lower OH1 voltage at 5ms to +100V from about +180V. To make vertical field rise quicker.
Dec 9 1997 09:38:25:790AM	971209003	Ian Hutchinson	Plasma to 1.56s. Still have the oscillation. EF3 noise goes away. Current hesitation is gone. 2MW RF. Move RCUR to .666m at .3s.
Dec 9 1997 10:01:45:210AM	971209004	Ian Hutchinson	Plasma till 1.56s. No improvemnet to oscillations. 2.2MW RF. RF loading feedback to -2000 from -1500 in segment 2.
Dec 9 1997 10:17:45:160AM	971209005	Ian Hutchinson	Plasma to 1.5s. Lower proportional gain from 8 to 6 one zcur 3 at .24s.
Dec 9 1997 10:38:52:490AM	971209006	Ian Hutchinson	Plasma to 1.5s. Major improvement in early oscillation. Go further on the zcur. Add gain to4 at 0.26s in addition to the gain 6 point at .24s. Raise nl04 demand to 1.5 at .5s. Raise kside main puff pressure to 29 psi.
Dec 9 1997 10:49:43:830AM	971209007	Ian Hutchinson	Plasma till 1.3s No RF. Gas stays on quite late. Eas off on the nl04 demand at about .3s. Raise zxl to -.015m to put strike points on the plate.
Dec 9 1997 11:04:52:840AM	971209008	Ian Hutchinson	fizzle - fields look normal - gas o.k. no sparker no changes for 009
Dec 9 1997 11:24:08:530AM	971209009	Ian Hutchinson	Dud OH2L pulls out @ -0.7sec all power supplies check out o.k.
Dec 9 1997 11:42:59:070AM	971209010	Ian Hutchinson	plasma - disrupts @ 1.43sec - breakdown @ 5msec - sparker worked - still a density burst @ 0.43sec for 011: slow down NL04 ramp (reaches maximum @ 0.65sec) draw PG3 voltage to 50V after 0.25sec
Dec 9 1997 12:03:05:500PM	971209011	Ian Hutchinson	Fizzle breakdown at 6msec no sparker on this one Br is ~ +1mTesla For 012: lower Br_0 offset to .006
Dec 9 1997 12:13:50:590PM	971209012	Ian Hutchinson	plasma - breakdown @ 5msec - Br_0 oscillating around 0.mT - sparker worked - density bump @ 0.4 almost all gone for shot 013: - RF_LOAD_E to -1800 (was -2000)
Dec 9 1997 12:33:35:750PM	971209013	Ian Hutchinson	Plasma - breakdown at 5.5msec (sparker worked) - slight hesitation in current rise For 014: RF_LOAD_E = -2000 (was -1800)
Dec 9 1997 12:42:12:770PM	971209014	Ian Hutchinson	Plasma - only one RF trip - breakdown @ 5msec; no hesitation
Dec 9 1997 01:17:03:330PM	971209015	Ian Hutchinson	Hutch back. Increase the nl04 programming to avoid density roll over. RF feedback to -2200. Plasma till 1.44s. Vertical oscillation at .9s, about 50Hz. RF Loading seems to be better controlled.
Dec 9 1997 01:32:57:480PM	971209016	Ian Hutchinson	No changes. Plasma till 1.43s 2.5MW with faults. Plasma is pulled very close to the limiter by the feedback. Next shot RF threshold to 2.7 from 2.6.
Dec 9 1997 01:54:09:430PM	971209017	Ian Hutchinson	Plasma. Some Mo injections. Raise zcur to -.013 from -.015. Ditto zxl. Argon off.
Dec 9 1997 02:10:13:590PM	971209018	Ian Hutchinson	Plasma till 1.54s. RF 2.6MW a couple of trips. zcur and zxl to -.011m. RF feedback to -2000.
Dec 9 1997 02:24:17:420PM	971209019	Ian Hutchinson	Plasma. RF 2.6MW Still having limiter contacts. Seems to coincide with Mo influx. Move rcur to .667 from .669 to try to stop limiter bumping.
Dec 9 1997 02:41:34:750PM	971209020	Ian Hutchinson	Plasma. Right gap now averaging about 6mm. Mo levels somewhat reduced. rcur to .665m, more of the same.
Dec 9 1997 02:42:01:910PM	971209021	Ian Hutchinson	Power Supply Fault. TF breaker pulled.
Dec 9 1997 03:38:59:560PM	971209022	Ian Hutchinson	Plasma. 10 Hz oscillation on power supplies. Looks like an Rcur problem. RF feedback? Shows predominantly on EF4, so it might be something else. Got a right gap averaging about 1cm. Turn off nl04 feedback at .8s Maintain gas puff at 40% till 1.05s.
Dec 9 1997 03:57:22:590PM	971209022	Ian Hutchinson	Disrupts at .77s. Slowly growing vertical instability. Seems to have been caused by the fact the RF transmitter E, that controls feedback, was turned on later, at .7s. This makes a big R jerk and then z is lost. RF feedback to -1500.
Dec 9 1997 04:07:40:000PM	971209024	Ian Hutchinson	Fizzle:disruption recovery. Tweak OH1 Voltage down at 5ms. Move rxl out by about 5mm.
Dec 9 1997 04:29:31:890PM	971209025	Ian Hutchinson	Plasma till 1.51. Repetitive H-L cycles cuased by RF trips as the H-mode develops. Rcur pulling is drastically reduced. rxl to .003m. Bruce wants more strike-point height.
Dec 9 1997 04:40:05:670PM	971209026	Ian Hutchinson	Fizzle. CII is up around .003. OH1 voltage lowered some more from 3ms on.
Dec 9 1997 04:49:10:370PM	971209027	Ian Hutchinson	Fizzle. Obviously I am not doing the right thing, but we got 40kA before hitting something. EF4 to -1330 from -1335.
Dec 9 1997 05:00:53:820PM	971209028	Ian Hutchinson	Plasma till 1.45s. Signs of vertical oscillation at .55s. Barely burns out. RF coupling worse than before. Fill to 17ms from 18.
Dec 9 1997 05:01:07:020PM	971209028	Ian Hutchinson	Fizzle.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:51:45:600AM	Plasma	Ok
2	09:09:36:270AM	Plasma	Ok
3	09:24:04:010AM	Plasma	Ok
4	09:38:13:950AM	Plasma	Ok
5	10:00:10:990AM	Plasma	Ok
6	10:17:22:420AM	Plasma	Ok
7	10:36:43:910AM	Plasma	Ok
8	10:52:02:330AM	Plasma	Ok
9	11:08:02:100AM	Plasma	Ok
10	11:25:39:190AM	Plasma	Ok
11	11:44:20:580AM	Plasma	Ok
12	12:04:08:190PM	Plasma	Ok
13	12:17:31:300PM	Plasma	Ok
14	12:35:16:910PM	Plasma	Ok
15	12:56:10:810PM	Plasma	Ok
16	01:14:50:500PM	Plasma	Ok
17	01:41:04:030PM	Plasma	Ok
18	01:52:32:330PM	Plasma	Ok
19	02:08:17:100PM	Plasma	Ok
20	02:22:52:750PM	Plasma	Ok
21	02:39:06:410PM	Plasma	Bad	tf ioc, self powered ckt fired
22	03:16:59:330PM	Plasma	Ok
23	03:37:26:560PM	Plasma	Ok
24	03:57:29:080PM	Plasma	Ok
25	04:08:20:610PM	Plasma	Ok
26	04:27:07:200PM	Plasma	Ok
27	04:38:30:170PM	Plasma	Ok
28	04:47:41:830PM	Plasma	Ok
29	04:58:55:620PM	Plasma	Ok